One of the change is the aeon shield consumption being reduced to 75 (from 125).
It's not the case of the UEF one.
Why ?
The reason behind is that the shield is what is needed to make the difference for aeon at T2.
It's what allow them to deal with seraphim/uef/cybran Bots, as they don't have any long ranged weapon.
They also need them to deal with mobile MML (their TMD don't handle mobile MML at all).
It's also what allow their navy to work.
125 E was 467 mass in T1 pgen. + 144 mass for the shield itself, it was 612 mass (1,7 obsidian) just to make aeon T2 units viable against others T2.
On the other side, UEF have a range bot that fill the role of counter for other bots, and they have a better dedicated naval shield, so I don't feel like they need the same buff.
A case of faction diversity I guess.
If you fear spam, remember that stacked shields (for navy) are still ineffective.
At least you know the reasoning behind now (you can of course discuss it, but you know how I love replays